Project Summary TR&D 1 TR&D 1 is devoted to the development of two pieces of unique instrumentation for magnetic resonance. The first of these is an 800 MHz/527 GHz DNP spectrometer. It will involve (1) completion of triple channel, low-temperature MAS probes with a 1.3 mm rotor ( r/2 >40 kHz at 85 K) and fabrication of additional probes for special purposes, (2) the cryogenics for MAS at 80 K, (3) corrugated waveguide to connect the gyrotron output to the probe, and (4) interfacing these components with a 527 GHz tunable gyrotron nearing completion. Upon completion the spectrometer will be the sole 800/527 instrument in North America. The second piece of instrumentation to be completed is an EPR driver for a 250 GHz gyroamplifier to perform pulsed DNP experiments. The research will involve (1) construction of a 250 GHz driver system based on a fast arbitrary waveform generator (AWG) that will us allow to perform pulse experiments such as NOVEL, the frequency swept integrated solid effect (FS-ISE) and time optimized pulsed (TOP) DNP in which the electron pulses are synchronous with the nuclear Larmor frequency (2) the driver will be interfaced to the amplifier through two active multiplier chains that will allow us to generate 600-1200 watts of 250 GHz microwave power and to detect 250 GHz EPR signals. (3) The amplifier will be use at cryogenic temperatures with a TE011 resonator and 1.3 mm or smaller rotor. The primary advantage of pulsed DNP is that it will permit us to circumvent the ?0-1 field dependence exhibited by CW DNP experiments.